MicroRNAs (miRNAs) are single-stranded non-coding small RNA molecules, typically in the length range of 21-23 nucleotides. Found in plants and animals, these short RNAs are important regulators of gene expression by way of silencing of specific target mRNAs and/or suppressing translation of specific target mRNAs. Well conserved across a broad spectrum of plant and animal species, miRNAs are believed to be a vital and evolutionarily ancient component of genetic regulation mechanism.
Since miRNAs were first recognized as a distinct class of biological regulators in the early 2000s, much effort has been devoted to miRNA research. It has been revealed that different sets of miRNAs are expressed in different cell types and tissues and that miRNAs play multiple roles during plant and animal development as well as in a variety of other biological processes. Furthermore, aberrant expression of miRNAs has been implicated in numerous disease states, including different types of cancer. Given the biological importance of miRNAs, there exists an urgent need for new and more effective means of miRNA delivery in various therapeutic applications as well as for useful research tools in the ongoing miRNA studies. This invention fulfills this and other related needs.